FILE - In this undated file image posted on Monday, June 30, 2014, by the Raqqa Media Center of the Islamic State group, a Syrian opposition group, which has been verified and is consistent with other AP reporting, fighters from the Islamic State group parade in Raqqa, north Syria. (AP Photo/Raqqa Media Center of the Islamic State group, File)

Would-be ISIS terrorists are taking more roundabout routes to Syria in an effort to make European authorities' attempts to catch them more difficult.